Geometric Innovation in Acoustic Emission: The Icosidodecahedron as a Novel Omnidirectional Source

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study was conducted using simulation in the EASE SpeakerLab program. The results are shown in graphs, which show the dependencies on the source radius, measurement distance, and frequency. At a frequency of 100 Hz, both objects exhibit omnidirectional radiation, which confirms the relevance of the tasks set and the significance of the data obtained. 

1. The simulation did not cover all possible combinations of parameters. Temperature differences were not taken into account, especially negative ones, since the material may not withstand cold or heat. The speed of sound propagation in the medium is also not set.
2.  At a distance of 10 meters, the icosadodecahedron maintains high omnidirectionality, which is important for practical applications. The speed of propagation of sound waves is not specified, if the walls have the ability to absorb or reflect sound, their resonance at different frequencies is also important for loud sounds. Is it important to identify this as one of the most significant results of the work as a novelty of the research?
3.  If the dodecahedron shows deviations from omnidirectionality at a distance of 20 meters, then the icosadodecahedron provides an ideal energy distribution. Is it necessary to clarify in detail the mechanism of dependence of these results? 

Comparison at different distances and frequencies, as well as the influence, especially of external parameters on the experimental results, require a more detailed description. The article can be published after minor clarifications that will help to better understand the specifics of the research. It corresponds to the profile of the journal and may be of interest to readers, and may also be published after minor clarifications.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presents a well-structured and innovative approach to omnidirectional acoustic sources, focusing on the icosidodecahedron geometry as a novel alternative to the traditional dodecahedral design. The theoretical framework is robust, and the inclusion of both practical implementation and psychoacoustic testing adds significant value to the work. The study's potential to influence acoustic measurement practices, particularly in reverberation time and sound insulation assessments, is promising. Additionally, the self-fabrication aspect is a commendable contribution to the Sound Engineering program in Bogotá, Colombia, and strengthens the manuscript’s relevance to applied research.

One of the manuscript’s strengths is the clear articulation of the importance of omnidirectional sources in acoustic measurements. The introduction provides a solid foundation for understanding the limitations of dodecahedral loudspeakers, and the justification for exploring icosidodecahedron geometry is well-explained. The manuscript also effectively highlights the complex mathematical formulation behind the geometry, while the self-fabrication initiative is a novel and commendable aspect that enriches the study. Moreover, the empirical support provided through psychoacoustic and perceptual tests is valuable in validating the source’s performance in real-world scenarios.

However, there are several areas that would benefit from further clarification and development. The manuscript mentions the more complex mathematical formulation for the icosidodecahedron geometry, but a clearer explanation of the specific advantages of this formulation in practical applications would benefit readers, especially those who may not be familiar with advanced acoustic geometry. A comparison with the dodecahedral design’s formula might help clarify the differences. Additionally, while the self-fabrication initiative is an interesting aspect of the study, more detailed information about the materials used, the fabrication process, and any challenges encountered during this phase would be helpful. Were the acoustic properties of the icosidodecahedron source tested during fabrication to ensure they met the theoretical design? Providing these details would enhance the transparency of the research.

The section on acoustic testing also lacks specific information on the testing protocols used. While the manuscript mentions psychoacoustic and perceptual tests, it would be helpful to clarify the methodologies and conditions under which these tests were conducted. For example, was the study focused on subjective listening tests, or were objective measurements, such as frequency response and directivity patterns, also included? Including more specifics on the test environment, demographics of the participants, and the number of trials would improve the reproducibility and credibility of the findings. Additionally, the manuscript would benefit from a direct comparison with other alternative geometries, such as the dodecahedron or more recent developments in omnidirectional source design. A detailed comparison in terms of radiation uniformity, directivity, and ease of fabrication would help readers better understand the unique advantages of the icosidodecahedron design.

The manuscript also mentions the results of psychoacoustic testing but does not provide a detailed interpretation of these results. A more comprehensive analysis of how the icosidodecahedron source performed in terms of listener perception—such as sound clarity, field uniformity, or overall sound quality—would be beneficial. Were there any significant differences in how the icosidodecahedron was perceived compared to traditional designs? Statistical analysis or visual representation of the perceptual results, such as graphs or charts, would further enhance the manuscript.

To improve the manuscript, I recommend expanding the mathematical descriptions and providing a step-by-step breakdown of the design process, perhaps supported by diagrams or flowcharts. Additionally, more technical detail on the fabrication process, including the materials used and how the acoustic properties were verified during production, would be valuable. A deeper discussion of the perceptual testing results, along with statistical analyses and graphical representations, would strengthen the conclusions drawn. Finally, a more thorough comparison to existing omnidirectional source designs would help place the icosidodecahedron in the broader context of recent research, showcasing its advantages and limitations relative to other alternatives. 

Additionally, I would like to point out that Figure 1 in its current form is of poor quality and difficult to interpret. The image does not clearly convey the necessary details of the icosidodecahedron geometry. As an alternative, the authors could consider describing the key elements of the figure in a well-organized table, which would provide clearer information and improve the overall readability of the manuscript. This approach could also help make the complex geometry more accessible to readers who may not be familiar with 3D models or visual representations of such designs.

   

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In the Introduction section, the authors are required to provide a more comprehensive review of related studies in order to clearly highlight the significance and novelty of the present work.

At the 10 kHz frequency band, the intrinsic directivity of a conventional 4–5 inch transducer already approaches ±30° (–6 dB). The manuscript appears to assume the transducer as a point source; however, no information is provided regarding the transducer model, physical dimensions, high-frequency directivity measurement data, or whether a waveguide or hemispherical baffle is employed. Please clarify how the intrinsic directivity of the transducer is separated from the overall directivity of the spherical array, so as to avoid misinterpreting the transducer beam pattern as array-induced interference.

What angular step size is used for the radiation sphere mapping? According to the sampling theorem, at 10 kHz (λ ≈ 3.4 cm), the Nyquist spatial frequency on a spherical surface with a radius of r = 20 m corresponds to approximately 0.17°. If the angular step is ≥ 5°, please justify why no visible aliasing appears in the radiation patterns, or alternatively, provide additional details on high-resolution scanning and the interpolation algorithms used.

In Section 5, a physical prototype is designed by the authors; however, no experimental validation is conducted to verify its effectiveness.

The authors are advised to include a discussion of the limitations of the present study in the Conclusions section.

Many of the cited references are relatively outdated. It is recommended to include more recent, high-quality journal publications to enhance the timeliness and relevance of the study.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have satisfactorily addressed all the reviewer comments in the revised version of the manuscript entitled “Geometric Innovation in Acoustic Emission: The Icosidodecahedron as a Novel Omnidirectional Source.” The revisions have significantly improved the clarity of the presentation, strengthened the theoretical justification, and enhanced the discussion of experimental results. The authors have now clearly described the methodology, and the data firmly supports the conclusions. The manuscript offers a fresh and significant addition to the field of acoustic emission and geometric source design. Therefore, I suggest accepting the manuscript for publication in its current form.

Reviewer 3 Report

Comments and Suggestions for Authors

I have no other comments.